US4427738A - Magnetic recording medium - Google Patents

Magnetic recording medium Download PDF

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Publication number
US4427738A
US4427738A US06/274,565 US27456581A US4427738A US 4427738 A US4427738 A US 4427738A US 27456581 A US27456581 A US 27456581A US 4427738 A US4427738 A US 4427738A
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US
United States
Prior art keywords
magnetic recording
recording medium
lubricant
tape
layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US06/274,565
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English (en)
Inventor
Masaaki Fujiyama
Nobutaka Yamaguchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujifilm Holdings Corp
Original Assignee
Fuji Photo Film Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fuji Photo Film Co Ltd filed Critical Fuji Photo Film Co Ltd
Assigned to FUJI PHOTO FILM CO., LTD. reassignment FUJI PHOTO FILM CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: FUJIYAMA, MASAAKI, YAMAGUCHI, NOBUTAKA
Application granted granted Critical
Publication of US4427738A publication Critical patent/US4427738A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
    • G11B5/735—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer characterised by the back layer
    • G11B5/7356—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer characterised by the back layer comprising non-magnetic particles in the back layer, e.g. particles of TiO2, ZnO or SiO2
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/90—Magnetic feature
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
    • Y10T428/256—Heavy metal or aluminum or compound thereof

Definitions

  • This invention relates to a magnetic recording medium capable of magnetic recording and reproduction at a high tape speed of 2 to 10 m/sec., and more particularly, to endless video tape having an improved lubricant layer.
  • the conventional endless tape used in car stereos is run in record or reproduce mode at a tape speed of 9.5 cm/sec.
  • Endless video tape must be run at a speed of at least 2 m/sec., usually at least 5 m/sec., if the purpose is to record and reproduce video signals rather than audio signals.
  • Running the conventional endless tape at a speed in the range of from 2 to 10 m/sec. has the following problems:
  • the first problem is that of the magnetic layer. This can be solved by using a magnetic Co-Fe base, CrO 2 or alloy powder as in 1/2 inch wide video tape. But to solve the second problem, a new technique has been necessary, because when the conventional endless tape is run at 2 to 10 m/sec. for 30 hours, wrinkles from cinching, abnormally high tape tension, and flaking of the lubricant layer make the tape unfit for further running.
  • one object of this invention is to provide a magnetic recording medium having a magnetic layer capable of recording and reproducing video signals and which can be run at a high speed of 2 to 10 m/sec.
  • Another object of this invention is to provide a magnetic recording medium of the type described above which withstands more than 150 hours of running and which is free from the flaking of the lubricant layer, as well as from wrinkles due to cinching.
  • a lubricant layer having a surface roughness (Ra) in the range of from 0.33 to 0.72 ⁇ m exhibits improved durability for a high tape speed of 2 to 10 m/sec.
  • a lubricant layer having the above defined surface roughness and which is 2.5 to 5 ⁇ m thick exhibits not only improved durability but also resistance to flaking.
  • this invention relates to a magnetic recording medium having a magnetic recording layer on one side of a non-magnetic base and a lubricant layer on the other side and which is used at a high tape speed of 2 to 10 m/sec., said lubricant layer having a thickness of 2.5 to 5 ⁇ m and a surface roughness (Ra) of 0.33 to 0.72 ⁇ m.
  • FIG. 1 is a cross-section of the conventional endless tape
  • FIG. 2 is a cross-section of the endless video tape of this invention.
  • FIG. 3 schematically represents the transport system of a machine for testing the characteristics of endless video tape.
  • a magnetic recording layer is formed on one side of a non-magnetic base and a lubricant layer is formed on the other side of the base to reduce the friction and provide suitable slippage between the layers in a tape roll.
  • the lubricant layer according to this invention comprises lubricant, binder and the like, preferably contains wax.
  • the lubricant layer preferably contains graphite as lubricant, and molybdenum disulfide or talc powder may also be used as lubricant.
  • the graphite comprises particles which preferably have an average diameter of 3 to 10 ⁇ m. Better results are obtained by using a diketone ##STR1## as wax in the lubricant layer.
  • R and R' which may be same or different, are each an aliphatic alkyl having 7 to 17 carbon atoms.
  • the wax are preferably an aliphatic alkyl ketone such as ##STR2## and the like. Diheptadecyl ketone of the formula ##STR3## is more preferred because an even higher durability is obtained.
  • the wax is preferably used in an amount of at least 0.5 wt. % based on the weight of lubricant (e.g., graphite).
  • binder examples include a vinyl chloride/vinyl acetate copolymer, vinyl chloride, polyurethane, vinyl chloride/acrylonitrile copolymer, cellulose derivative, polyisocyanate, epoxy resin, and mixtures thereof.
  • the binder is used in an amount of about 30 to 300 parts by weight, preferably 50 to 200 parts by weight, based on 300 parts by weight of lubricant.
  • the magnetic recording layer according to this invention may be formed of a known composition containing a magnetic substance, binder, lubricant, abrasive, and dispersant.
  • the binder examples include a vinyl chloride/vinyl acetate copolymer, vinyl chloride, polyurethane, vinyl chloride/acrylonitrile copolymer, cellulose derivative, polyisocyanate, epoxy resin, and mixtures thereof.
  • Examples of the lubricant are silicone oil, aliphatic acid, fluorine oil, and aliphatic acid ester.
  • Examples of the abrasive are Cr 2 O 3 , Al 2 O 3 , SiC, and gamma-Fe 2 O 3 .
  • Examples of the dispersant are lecithin, humic acid and oleic acid.
  • Other additives include carbon black.
  • the non-magnetic base used in this invention may be made of any conventional material for non-magnetic base, and preferred examples include polyethylene terephthalate, triacetyl cellulose, diacetyl cellulose, vinyl chloride, polyimide, polypropylene, and polyethylene naphthalate.
  • the base preferably has a strength of at least 40 kg/mm 2 .
  • a polyethylene terephthalate base 15 ⁇ m thick was coated with a magnetic layer of the formulation indicated below to a dry thickness of 5 ⁇ m.
  • the other side of the base was coated with a lubricant layer of the formulation indicated below.
  • the resulting film was calendered and slit to 1/4 inch wide as in the production of the conventional small video tape.
  • Twenty-six tape samples were prepared by repeating the above procedure but changing the thickness, average particle size and surface roughness of the lubricant layer, as well as the amount of wax used (for details, see Table 1 below). The samples were tested for various parameters according to the methods specified below.
  • a tape pack (1/4 inch wide ⁇ 50 m long) was set in a testing machine schematically shown in FIG. 3 and was run continuously at a speed of 5 m/sec. The time (in hours) required for the tape to show various defects (e.g., tape stop, breakage, and cinching) was measured.
  • the guide assembly of the machine used in the durability test (1) was visually checked for the presence of dirt.
  • NTSC National Television System Committee
  • the tape lead-out tension at a point T 1 in FIG. 3 was measured.
  • the surface roughness is represented by Ra or center line average roughness as defined in JIS BO601.
  • the Ra value was measured with "Surfcom 30B", a surface roughness meter of Tokyo Seimitsu Co., Ltd.
  • FIG. 1 A cross-section of the conventional endless tape is shown in FIG. 1.
  • FIG. 2 A cross-section of the endless video tape of this invention is shown in FIG. 2, wherein 1 is a magnetic layer, 2 is a base, and 3 is a lubricant layer.
  • the transport system of a machine used for testing the characteristics of endless video tape is schematically shown in FIG. 3 wherein 4 is endless video tape, 5 and 5' are a roller, 6 is a record/reproduce head, 7 is a pinch roller, and 8 is a capstan.
  • Sample No. 1 which used a lubricant layer similar to that used in endless audio tape was inferior to most of the other samples with respect to durability (only 5 hrs), flaking of the lubricant layer, the number of dropouts, video quality (jitter) at tape splice, and wrinkles from cinching.
  • Sample Nos. 2 to 8 used lubricant layers containing 3 wt. % of wax and having a thickness that varied from 0.8 to 10 ⁇ m. The thicker the lubricant layer, the more durable and resistant to flaking the layer was.
  • Sample Nos. 9 to 15 used lubricant layers containing from 0 to 7 wt. % of wax based on the weight of graphite.
  • the lubricant layers containing 0.5 wt. % or more wax had great durability and were highly resistant to flaking.
  • Sample Nos. 16 to 19 used lubricant layers that contained graphite particles whose size was varied from 1 to 10 ⁇ m. Better results were obtained with a particle size of 3 ⁇ m or more, but a particle size of 10 ⁇ m was not effective in providing improved durability.
  • Sample Nos. 20 to 22 used bases having a strength of from 20 to 52 kg/mm 2 . Sample Nos. 21 and 22 using a stronger base were better than Sample No. 20 with respect to durability and video quality at tape splice.
  • Sample Nos. 23 to 26 used lubricant layers having a surface roughness (Ra) varying from 0.29 to 0.85 ⁇ m.
  • the magnetic recording medium achieves the best result when it uses a lubricant layer that contains wax and which has the thickness, surface roughness and particle size defined herein, and if it uses a strong base. But the objects of this invention are fully achieved when the lubricant layer has the thickness and surface roughness defined herein.
  • the advantages of the magnetic recording medium of this invention are obtained when the tape speed relative to the fixed video head is in the range of from 2 to 10 m/sec., and they include high durability, minimum flaking of lubricant layer, small number of dropouts, high video quality at tape splice, low tape lead-out tension, absence of wrinkles due to cinching.

Landscapes

  • Magnetic Record Carriers (AREA)
  • Paints Or Removers (AREA)
  • Lubricants (AREA)
US06/274,565 1980-06-17 1981-06-17 Magnetic recording medium Expired - Fee Related US4427738A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP8156980A JPS578926A (en) 1980-06-17 1980-06-17 Magnetic recording body
JP55-81569 1980-06-17

Publications (1)

Publication Number Publication Date
US4427738A true US4427738A (en) 1984-01-24

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US06/274,565 Expired - Fee Related US4427738A (en) 1980-06-17 1981-06-17 Magnetic recording medium

Country Status (3)

Country Link
US (1) US4427738A (US08197722-20120612-C00042.png)
JP (1) JPS578926A (US08197722-20120612-C00042.png)
DE (1) DE3123803A1 (US08197722-20120612-C00042.png)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4567083A (en) * 1983-10-17 1986-01-28 Tdk Corporation Magnetic recording medium
US4579778A (en) * 1983-04-25 1986-04-01 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4612235A (en) * 1982-06-29 1986-09-16 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4687706A (en) * 1983-04-11 1987-08-18 Fuji Photo Film Co., Ltd. Magnetic recording medium
US5580633A (en) * 1992-04-24 1996-12-03 Tdk Corporation Magneto-optical disc having a protective layer of cured radiation curable resin containing carbon particles
US5620765A (en) * 1995-05-02 1997-04-15 Eastman Kodak Company Aqueous backing for digital optical media
EP2546535A1 (en) * 2010-03-09 2013-01-16 Taiho Kogyo Co., Ltd Sliding member

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0093194B1 (en) * 1982-04-30 1988-08-31 Matsushita Electric Industrial Co., Ltd. Magnetic recording medium
US4446193A (en) * 1983-04-29 1984-05-01 International Business Machines Corporation Process for chemically bonding lubricant to an information carrier and products thereof
JPS605423A (ja) * 1983-06-22 1985-01-12 Fujitsu Ltd 連続磁性膜型磁気記録媒体
JPS6025074A (ja) * 1983-07-21 1985-02-07 Fuji Photo Film Co Ltd フレキシブル磁気デイスク
DE4300858A1 (de) * 1993-01-15 1994-07-21 Basf Magnetics Gmbh Magnetisches Aufzeichnungsmedium

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2352958A1 (de) 1973-10-23 1975-04-30 Basf Ag Schichtmagnetogrammtraeger mit gleitfaehiger rueckseitenbeschichtung
US3993824A (en) 1974-02-15 1976-11-23 Fuji Photo Film Co., Ltd. Recording member comprising a substrate with a magnetic lager on one surface and a lubricating lager on the opposed surface
US4071654A (en) 1974-08-28 1978-01-31 Fuji Photo Film Co., Ltd. Magnetic recording member
US4328935A (en) 1980-06-12 1982-05-11 Minnesota Mining And Manufacturing Company Flexible magnetic recording tape having low-friction backside coating
DE2501372C2 (de) 1975-01-15 1983-10-27 Basf Ag, 6700 Ludwigshafen Flexible Schichtmagnetogrammträger mit Rückseitenbeschichtung und Verfahren zu ihrer Herstellung

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5337003B2 (US08197722-20120612-C00042.png) * 1974-05-22 1978-10-06

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2352958A1 (de) 1973-10-23 1975-04-30 Basf Ag Schichtmagnetogrammtraeger mit gleitfaehiger rueckseitenbeschichtung
US3993824A (en) 1974-02-15 1976-11-23 Fuji Photo Film Co., Ltd. Recording member comprising a substrate with a magnetic lager on one surface and a lubricating lager on the opposed surface
US4071654A (en) 1974-08-28 1978-01-31 Fuji Photo Film Co., Ltd. Magnetic recording member
DE2501372C2 (de) 1975-01-15 1983-10-27 Basf Ag, 6700 Ludwigshafen Flexible Schichtmagnetogrammträger mit Rückseitenbeschichtung und Verfahren zu ihrer Herstellung
US4328935A (en) 1980-06-12 1982-05-11 Minnesota Mining And Manufacturing Company Flexible magnetic recording tape having low-friction backside coating

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4612235A (en) * 1982-06-29 1986-09-16 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4687706A (en) * 1983-04-11 1987-08-18 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4579778A (en) * 1983-04-25 1986-04-01 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4567083A (en) * 1983-10-17 1986-01-28 Tdk Corporation Magnetic recording medium
US5580633A (en) * 1992-04-24 1996-12-03 Tdk Corporation Magneto-optical disc having a protective layer of cured radiation curable resin containing carbon particles
US5620765A (en) * 1995-05-02 1997-04-15 Eastman Kodak Company Aqueous backing for digital optical media
EP2546535A1 (en) * 2010-03-09 2013-01-16 Taiho Kogyo Co., Ltd Sliding member
CN102918286A (zh) * 2010-03-09 2013-02-06 大丰工业株式会社 滑动部件
EP2546535A4 (en) * 2010-03-09 2013-09-18 Taiho Kogyo Co Ltd SLIDING MENT
AU2011225590B2 (en) * 2010-03-09 2014-11-20 Taiho Kogyo Co., Ltd. Sliding member
CN102918286B (zh) * 2010-03-09 2016-04-06 大丰工业株式会社 滑动部件

Also Published As

Publication number Publication date
DE3123803C2 (US08197722-20120612-C00042.png) 1989-04-06
DE3123803A1 (de) 1982-03-25
JPS6228488B2 (US08197722-20120612-C00042.png) 1987-06-20
JPS578926A (en) 1982-01-18

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